ArticleOriginal scientific text
Title
Marczewski-Burstin-like characterizations of σ-algebras, ideals, and measurable functions
Authors 1, 2
Affiliations
- Department of Mathematics, Auburn University, Auburn, AL 36849-5310, U.S.A.
- Department of Mathematics, Tuskegee University, Tuskegee, AL 36088, U.S.A.
Abstract
ℒ denotes the Lebesgue measurable subsets of ℝ and denotes the sets of Lebesgue measure 0. In 1914 Burstin showed that a set M ⊆ ℝ belongs to ℒ if and only if every perfect P ∈ ℒ$ℒ_0 $ℒ_0!$! which is a subset of or misses M (a similar statement omitting "is a subset of or" characterizes ). In 1935, Marczewski used similar language to define the σ-algebra (s) which we now call the "Marczewski measurable sets" and the σ-ideal which we call the "Marczewski null sets". M ∈ (s) if every perfect set P has a perfect subset Q which is a subset of or misses M. M ∈ if every perfect set P has a perfect subset Q which misses M. In this paper, it is shown that there is a collection G of sets which can be used to give similar "Marczewski-Burstin-like" characterizations of the collections (sets with the Baire property in the wide sense) and FC (first category sets). It is shown that no collection of sets can be used for this purpose. It is then shown that no collection of Borel sets can be used in a similar way to provide Marczewski-Burstin-like characterizations of (sets with the Baire property in the restricted sense) and AFC (always first category sets). The same is true for U (universally measurable sets) and (universal null sets). Marczewski-Burstin-like characterizations of the classes of measurable functions are also discussed.
Keywords
Baire property, Marczewski measurable, Lebesgue measurable
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